Message-ID: <CAMk+s2S3Y_mt0rQNN=rfB0Eor5QiOb3iQiS3=VamvrmSr_+p9Q@mail.gmail.com>
Date: 2017-02-08T09:27:33Z
From: Luigi Marongiu
Subject: fine tune changepoint
Dear all,
I am using the package changepoint to identify a cut-off between positive
and negative values for an assay. I followed the vignette of the package
and the results are replicated, so I tried with a dataset of my choice. In
the assay, the positive have a value above 0.8 and the negative below 0.6,
so i did:
set.seed(10)
my.data <- c(rnorm(100, 0.8, 0.1), rnorm(100, 0.6, 0.1))
plot(my.data)
cp <- cpt.mean(my.data, method='PELT')
cpts(cp)
plot(cp, type='l', cpt.col='blue', xlab="Index", cpt.width=4)
It is visible that the data is clearly separated in two clusters, but the
algorithm did not find any change point. I tried also the other methods of
the function but no change point was found.
How can I fine tune the analysis to identify a change point to use as
cut-off? such fine-tuning should also be generic because should be applied
to any dataset.
thank you
L.
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